Acidified soils caused toxic aluminum in 66 percent of 565 assessed streams. Diatoms and aquatic macroinvertebrates were moderately to severely affected. These effects have not improved in areas surveyed in the early 1980s

Previous analysis showed this area to have reduced macroinvertebrate biodiversity, an important measure of ecosystem health. New observations indicate that conditions have improved; report includes methods and results of sampling.

A web-enabled database that provides for the capture, curation, integration, and delivery of bioassessment data collected by USGS, principally macroinvertebrate, algae, fish, and supporting habitat data from rivers and streams.

Sixty-five sampling sites, selected by a statistical design to represent lengths of perennial streams in North Dakota, were chosen to be sampled for water chemistry and mercury in fish tissue to establish unbiased baseline data.

Sixty-five sampling sites, selected by a statistical design to represent lengths of perennial streams in North Dakota, were chosen to be sampled for fish and aquatic insects (macroinvertebrates) to establish unbiased baseline data.

Macroinvertebrate data collected by USGS or USFS from 73 sites from 2000 to 2007 and algal data collected from up to 26 sites between 2000 and 2001 in the Eagle River watershed, with emphasis on methods of sample collection and data processing.

Change in streams accompanying land and water use may affect benthic invertebrate assemblage composition and structure through changes in density of invertebrates or taxa richness, the number of different species living in the stream.